From: Intransition Date: 2012-06-26T04:57:14+09:00 Subject: Re: Enumerable#unassociate ------=_Part_93_3469839.1340654231911 Content-Type: multipart/alternative; boundary="----=_Part_94_33538079.1340654231911" ------=_Part_94_33538079.1340654231911 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit > > On Monday, June 25, 2012 12:00:01 PM UTC-4, Robert Klemme wrote: And what's the use case for *that* method? > > To convert an Enumerable to a Hash. Sorry, I should have specified that. > I have no name for it yet, so call it #h. >> > >> > # Convert an Enumerable object to a Hash. >> > # >> > # [:a, 1, :b, 2].h >> > # #=> {:a=>1, :b=>2} >> > # >> > # [:a, 1, :b, 2, :a, 3].h{ |v0,v1| v0.to_i + v1 } >> > # #=> {:a=>4, :b=>2} >> > # >> > def h(init={}) >> > h = init >> >> You never assign h nor init so you could completely get rid of h. > > ??? What about `h[k] = v`, or am I misunderstanding? > Btw, if you call the argument Hash "init" I would not necessarily >> expect it to be modified. Maybe it's better to do >> >> h = init.dup >> >> Or, to save one instantiation >> >> def h(init = nil) >> h = init ? init.dup : {} >> >> > if block_given? >> > each_slice(2) do |k,v| >> > h[k] = yield h[k], v >> >> I find it strange that you yield h[k] and not k. The caller can never >> know what k was, while if you pass k he can look up in init and obtain >> the value you now yield. > > The idea behind that is to allow Symbol#to_proc to be useful. a = [:a, 1, :b, 2, :a, 3] i = Hash.new{ |h,k| h[k] = [] } a.h(i, &:+) #=> {:a=>[1,3], :b=>[2]} I considered other interfaces to the block but this one seemed like it would be the most useful b/c of this. It's totally mysterious what you are after here. The fact that you do >> not have a name yet might be indicative that this methods are probably >> not such a good idea. They do not look generally useful to me. > > No, that's me simply not giving enough initial context, which sometimes I do so not to skew others consideration. But not very helpful in the case, clearly. ------=_Part_94_33538079.1340654231911 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable

On Monday, June 25, 2012 12:00= :01 PM UTC-4, Robert Klemme wrote:

And what's the use case for *that* method?

To convert an Enumerable to a= Hash. Sorry, I should have specified that.

> I have no name for it yet,= so call it #h.
>
> # Convert an Enumerable = object to a Hash.
> #
> # [:a,= 1, :b, 2].h
> # #=3D> {:a=3D>1, :b=3D>2= }
> #
> # [:a, 1, :b, 2, :a, 3= ].h{ |v0,v1| v0.to_i + v1 }
> # #=3D> {:a=3D&g= t;4, :b=3D>2}
> #
> def h(init=3D{= })
> h =3D init

You never assign h n= or init so you could completely get rid of h.

??? What about `h[k] =3D v`, or am I misundersta= nding?

<= blockquote class=3D"gmail_quote" style=3D"margin-top: 0px; margin-right: 0p= x; margin-bottom: 0px; margin-left: 0.8ex; border-left-width: 1px; border-l= eft-color: rgb(204, 204, 204); border-left-style: solid; padding-left: 1ex;= ">Btw, if you call the argument Hash "init" I would not necessarily <= br>expect it to be modified. Maybe it's better to do

h = =3D init.dup

Or, to save one instantiation

def h(= init =3D nil)
h =3D init ? init.dup : {}

> = if block_given?
> each_slice= (2) do |k,v|
> h[k] =3D yield h[k],= v

I find it strange that you yield h[k] and not k. The = caller can never
know what k was, while if you pass k he can look = up in init and obtain
the value you now yield.
<= /blockquote>

The idea behind that is to allow Symbol#t= o_proc to be useful.

a =3D [:a, 1, :b, 2, :a, 3]

i =3D Hash.new{ |h,k| h[k] =3D [] }
= ; a.h(i, &:+) #=3D> {:a=3D>[1,3], :b=3D>= ;[2]}

I considered other interfaces to the = block but this one seemed like it would be the most useful b/c of this.

It's totally mysterious what you are after here. &nbs= p;The fact that you do
not have a name yet might be indicative tha= t this methods are probably
not such a good idea. They do no= t look generally useful to me.

No, that's me simply not giving enough initial context, which someti= mes I do so not to skew others consideration. But not very helpful in the c= ase, clearly.
------=_Part_94_33538079.1340654231911-- ------=_Part_93_3469839.1340654231911--